The use of clutches in motor vehicle power trains has been troubled over the years with the problem of torsional vibration of the connected elements of the power train. To neutralize the torsional vibrations emanating from a vehicle engine which would otherwise cause disturbing noises in the transmission and driveline, a vibration damper has been utilized in the friction clutch assembly ahead of a manually operated transmission. A vibration dampener may also be used where a lock-up clutch is inserted in a torque converter for an automatic transmission.
A vibration damper assembly will normally include an output hub internally splined to an output shaft, a radial flange on the hub, a clutch plate and a spring retainer plate sandwiching the hub flange, and a plurality of damper springs received in circumferentially spaced aligned sets of openings in the plates and flange. The clutch plate carries the friction surfaces adjacent its outer periphery and is secured to the retainer plate by a plurality of rivets extending through recesses in the flange. Friction washers may be positioned between the flange and plates adjacent the hub. However, where the damper design provides for a constant rate of energy dissipation, the assembly has many times proved to be unsatisfactory, and the present invention overcomes the problems of prior designs.